The aim of this project is to study the processes involved in the assembly of the extracellular matrix in connective tissues. Specifically, the project is designed to 1) examine interactions between fibronectin and procollagen on the cell surface during matrix formation, 2) identify cellular structures (i.e. microfilaments, filopodia) responsible for the formation of fibronectin and fibronectin-collagen filaments, and 3) determine the orientation of fibronectin in fibronectin and collagen containing filaments. Specimens will be plunge frozen, partially freeze-dried and coated at low temperature with chromium or tungsten. The specimens will then be viewed at low temperature in the FESEM.